Species Area curve relevant

TLS Online TPP Program

#Id: 7517

#Unit 6. System Physiology – Plant

Auxin is the only plant growth hormone known to be transported polarly.  Auxin efflux takes place by PIN proteins

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#Id: 7518

#Unit 6. System Physiology – Plant

Auxin influx 

Auxin can enter plant cells from any direction by either of two mechanisms:

Passive diffusion of the protonated (IAAH) form across the phospholipid bilayer

Secondary active transport of the dissociated (IAA–) form via a 2H+–IAA– symporter

The dual pathway of auxin uptake arises because the passive permeability of the membrane to auxin depends strongly on the apoplastic pH.

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#Id: 7519

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 7520

#Unit 6. System Physiology – Plant

Polar transport require energy and is gravity independent

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#Id: 7521

#Unit 6. System Physiology – Plant

Several compounds have been synthesized that can act as auxin transport inhibitors (ATIs), including

NPA (1-Nnaphthylphthalamic acid)

TIBA (2,3,5-triiodobenzoic acid)

CPD( 2- carboxyphenyl-3-phenylpropane-1,3- dione)

NOA ( naphthoxyacetic acid)

Gravacin

TLS Online TPP Program

#Id: 7522

#Unit 6. System Physiology – Plant

NPA, TBA, CPD and gravacin are auxin efflux

inhibitors

NOA is an auxin influx inhibitor

AEIs can interfere with the trafficking of the plasma membrane proteins to which they bind, apparently by altering protein-preotein interactions.